Rotary grate



NOV. 3, C. M, SHOTT ROTARY GRATE Filed Sept. 8, 1934 2 Sheets-Sheet l C.M. SHOTT ROTARY GRATE Nov. 3, 1936.

2 sheets-sheet 2 Filed Sept. 8, 1954 h CMSWZ Patented Nov. 3, 1936UNITED STATES PATENT OFFICE Kleenburn Stoker Corporation,

Kleenburn,

Wyo., a corporation of Wyoming Application September 8, 1934, Serial No.743,270

7 Claims.

This invention relates to the class of fuel grates and pertainsparticularly to an improved rotary grate structure.

The primary object of the present invention is to provide a novel typeof rotary grate in which air may be fed through the grate to the fuelthereon but without permitting any of the fuel to pass through the gratestructure.

Another object of the invention is to provide 10 an improved form ofgrate made up of a plurality of coaxially arranged elements ofconstantly decreasing diameter and maintained in vertically spacedrelation so that air may be fed therethrough to fuel deposited upon thesurface,

without permitting any of the fuel or ash from falling through into theunderlying air supply chambers.

A further object of the invention is to provide an improved gratestructure which is designed for rotation to effect a progressive feedingof air therethrough from a point of supply, in which a novel retainerunit is employed for removably supporting the sectionally constructedgrate units.

'I'he invention will be best understood from a consideration of thefollowing detailed description taken in connection with the accompanyingdrawings forming part of this specication, with the understanding,however, that the in- Vention is not confined to any strict conformitywith the showing of the drawings but may be changed or modified so longas such changes or modifications mark no material departure from thesalient features of the invention as expressed in the appended claims.

In the drawings:-

Figure l is a vertical section on the line I--I of Figure 2, showing thegrate structure embodying the present invention with a portion of thegrate unit removed and with the structure disposed in the lower part ofa conventionally illustrated furnace.

Figure 2 is a view in top plan of a major portion of the grate structureshowing sections oi 4 the grate unit removed.

Figure 3 is a sectional View taken upon the n through the grate unitonly on the line 'I-'I in Figure 2.

Referring to the drawings, the numeral I indicates the lower portion ofa conventionally illustrated furnace structure within which the grate 5structure embodying the present invention is shown.

The present grate structure comprises a central air supply unit 2 whichconsists of a lower casing 3 into the side wall of which an air sup- 10ply pipe 4 extends which may receive air under pressure from anysuitable mechanism such as a fan or the like. The casing 3 has aninwardly extending annular top flange 5, and resting upon this flange isthe vertically disposed hollow cylin- 15 der 6, which has an outwardlyextending surrounding base flange 'I which rests upon the flange 5 andis bolted thereto in the manner illustrated. Surrounding the cylinder 6and resting upon the flange 'I is an annular bearing metal ring 8, thepurpose for which will be hereinafter set forth. The wall of thecylinder 6 is provided with a series of apertures S which extendcircumferentially thereof and are of graduated 25 heights from one endof the series to the other so that the amount of air passing throughthese apertures in progressing from one end of the series to the other,is gradually cut down.

Surrounding the air cylinder 6 is a grate re- 30 taining unit indicatedgenerally by the numeral IU. This unit comprises a circular base plateor floor I I which is centrally apertured to receive the cylinder 6 andis provided at its under side around the central aperture with thethickened 35 bearing portion I2 which rests upon and turns on the ring8.

Formed integral with the grate retainer unit floor I I is a series ofvertically disposed partitions or Webs I6 which extend radially,terminating 40 at their outer ends short of the outer edge of the floorand at their inner ends being spaced to form the necessary .centralyunobstructed area into which theair cylinder 6 must extend. The inneredges of these webs or partitions I3 are formed 45 to conform closely tothe surface contour of the cylinder 6 and at the center of the retainerunit and above the cylinder 6, they are integrally joined to andconnected by the head or cap I4, which rests upon the topof the cylinder6, as 50 shown in Figure 1 and which has formed integral therewith theupwardly extending central post I5. This post I5 is upon the verticalaxis of the cylinder 6 and forms an axis or pivot for the gratestructure and for retaining in position thereover the fuel feedingmechanism hereinafter described.

The top edge of each of the walls or partitions I3 is cut out in steppedformation, as indicated at I6, for the purpose of better retaining inposition the hereinafter described grate units.

Surrounding the bottom or floor plate I I of the grate retainer unit isa sectional expansion ring I1, the sections of which are joined inoverlapping relation, as indicated at I8 in Figure 2. As illustrated inFigure l, a portion of this expansion ring overlies and rests upon thetop surface of the floor plate II and at intervals the ring Il hasextending inwardly from each of its sections the integral ears I9 whichare bolted to the floor plate II, as indicated at 20 in Figure 6.

The expansion ring I'I is formed to provide about its outer edge theupwardly inclined lip 2| which coacts with the adjacent portion of thefurnace structure to maintain the fuel and ash on the grate structure.This lip also corresponds with the formation of portions of the grateunit to form the completed grate structure, as will be more fullydescribed.

The grate unit is indicated generally by the numeral 22 and comprises aplurality of annular plates 23, which are coaxially arranged and ofvarying diameters so that when disposed one above the other with theplate of largest diameter at the bottom of the series, they form anapproximately conical structure. These annular plates 23 may be and areillustrated as divided into a number of segments, the number hereillustrated being four, although it is to be understood that the platesmay be divided into a greater number of segments or need not be dividedat all if their assembly and use as an integral unit is found feasible.

For the purpose of maintaining the plates 23 in coaxial relation and inthe spaced relation in which they are shown in Figure l, there is joinedtherewith, or cast integral therewith, the radially disposed ribs 24, 25and 26. The ribs 24 are relatively wide and heavy, as illustrated inFigure 3,

`- while the ribs 25 are narrower or of less depth and have their underedges cut out or formed in stepped design to conform with and rest uponthe steps of the grate retainer webs or partitions I3. Between the ribs24 and 25 are located the ribs 26 which, as shown in Figure 2, arerelatively short, extending radially of the grate unit only a portion ofthe distance which the other ribs extend.

In the present illustration of the grate unit structure, the same isdivided into four sections and in assembling these sections upon thegrate retainer I0, the adjoining or abutting edges are formed to providethe coacting channel and tongue 2l and 28, respectively, to form theoverlapping joint illustrated in Figure 4.

The ribs 24, 25 and 26 which connect the divided annular grate platestogether serve also, as previously stated, to maintain these plates invertically spaced relation so as to provide the air passageways 29between the plates. Through these passageways, the air is forced fromthe areas or chambers formed between the partition plates I3 of thegrate retainer structure, and as will be readily apparent, as the grateis rotated, each of certain of these areas between the partitions I3will receive a different amount of air from the others because of thevarying sizes of the air openings 9 formed in the wall of the cylinder6, before which openings the partitions pass.

As illustrated in Figures l and 2, each of the annular plates 23 of thegrate structure has an upwardly inclined top surface extending to itsouter edge from a line lying slightly beyond the periphery of the nextoverlying plate, thus forming a peripheral lip 30. These lips 30 of thegrate plates together with the lip 2I of the expansion ring, serve toretain in place fuel which is discharged onto the grate by forming whatamounts to a series of annular pockets. In these annular pockets, thefuel lodges and is burned.

In order to further assist in retaining the joined grate plates inposition, the bottoms thereof are provided at intervals with downwardlyprojecting lugs 32 which, as shown in dotted lines in Figure 2, opposethe inner edge of the expansion ring Il, so as to prevent any radialmovement of the sections into which the joined grate plates may bedivided.

While any satisfactory means of discharging fuel onto the grate may beemployed, it is preferred that an endless feed arrangement of thecharacter illustrated in Figure l be used. This feed comprises a tube orcasing 33 which is provided with an outlet or discharge opening 34 overthe grate and which has at its inner end the ring 35, which receives thepost I5. Within the tube 33 is a screw conveyor 36 by which the fuel inthe proper condition of neness is fed through the opening 3d. Extendingdownwardly from the fuel conducting tube 33 is a sweep apron 31, whichhas its lower edge in close proximity to the grate surface and whichserves to wipe off the ash before fresh fuel is added to the grate.

Any suitable means may be employed for rotating the grate structuresuch, for example, as the annular gear 38 secured to the under side ofthe grate retainer unit and connected with a pinion 39 which is drivenin any desired manner through the medium of the shaft 40.

The fuel feed means, driving means and graduated air supply means hereillustrated forms the subject-matter of prior Patent 1,914,873.

What is claimed isz- 1. In a grate structure, a plurality of coaxiallyarranged annular plates of different diameters arranged in superposedxed relation to form an f approximately conical structure, each of saidplates which lies beneath an adjacent plate being of an interiordiameter materially less than the outside diameter of the overlyingplate whereby an overlap of the plates is formed, and means connectingand securing the plates` in vertically spaced relation wherebyhorizontal air passages are formed therebetween, each of said annularplates having a top area which is upwardly and outwardly inclined toform a fuel retaining lip, said lip being formed throughout thecircumferential extent of the plate and having an interior diameterslightly greater than the overall diameter of the superimposed plate.

2. In a rotary grate structure, a grate unit retainer, comprising a baseplate having a central aperture, a plurality of vertically disposedpartitions each having a lower edge joined throughout its length withsaid plate and disposed about and radiating from the aperture andterminating adjacent to the outer edge of the plate, the top edges ofsaid partitions being outwardly and downwardly inclined and in steppedformation, a cylindric vertical structure projecting upwardly throughthe aperture of said plate and constituting a pivot about which theplate may be rotated,

said partitions abutting and moving about the cylindric structure withthe plate, and a grate unit comprising a plurality of vertically spacedcoaxially arranged annular members disposed in coaxial relation with theplate and resting upon the stepped surfaces of said partitions.

3. In a rotary grate structure, a grate unit retainer, comprising a baseplate having a central aperture, a plurality of vertically disposedpartitions disposed about and radiating from the aperture and joinedthroughout their radial extent with and terminating adjacent to theouter edge of the plate, the top edges of said partitions beingoutwardly and downwardly inclined and in stepped formation, a cylindricvertical structure projecting upwardly through the aperture of saidplate and constituting a pivot about which the plate may be rotated, aplurality of segments of annuli disposed in coaxial stepped relation onthe stepped surfaces. of said partitions and coaxial with said base,said segments uniting to form annular members, and rib membersconnecting said segments and maintaining the same in vertically spacedrelation to form air passageways therebetween and against relativemovement.

4. In a rotary grate structure, a grate unit retainer, comprising a baseplate having a central aperture, a plurality of vertically disposedpartitions integral with said plate and disposed about and radiatingfrom the aperture, the top edges of said partitions being outwardly anddownwardly inclined and in stepped formation, a cylindric verticalstructure projecting upwardly through the aperture of said plate andconstituting a pivot about which the plate may be rotated, a grate unitcomprising a plurality of vertically spaced coaxially arran-ged annularplates disposed in coaxial relation with the base plate and resting uponthe stepped surfaces of said partitions, and a sectional ring encirclingsaid base plate and the outer ends of said partitions and secured to thebase plate adjacent the periphery of the same, said ring facilitatingexpansive movement of the parts without breakage.

5. In a grate structure, a vertically disposed body of circular crosssection having an encircling ange at its lower end, a circular platehaving a central opening through which said vertical body projects andhaving a bearing surface upon its under side encircling the opening andresting upon said flange, a plurality of vertically disposed partitionsjoined to and carried by said plate and extending radially thereof andeach having an inner vertical edge in wiping contact with said verticalbodyl and further having its top edge inclined downwardly toward theouter edge of the plate and formed into a series of steps, said platehaving its periphery beyond the outer edges of the partitions, aplurality of grate plates of annular configuration, disposed coaxiallywith one another and with the vertical body, said plates being ofdifferent diameters and resting upon the stepped top edges of saidpartitions to form a substantially conical structure, means securingsaid grate plates together in vertically spaced overlapping relation,and means for rotating the base plate and elements supported therebyabout the vertical body, said vertical body being formed to facilitatethe discharge of air therethrough into the areas between the saidpartitions.

6. In a grate structure, a vertically disposed body of circular crosssection having an encircling flange at its lower end, a circular baseplate having a central opening through which said vertical body projectsand having a bearing surface upon its under side encircling the openingand resting upon said flange, a plurality of vertically disposedpartitions carried by said plate and extending radially thereof and eachhaving an inner vertical edge in wiping contact with said vertical bodyand further having its top edge inclined downwardly toward the outeredge of the plate and formed into a series of steps, a plurality ofgrate plates of annular configuration and of different diameters,disposed coaxially with one another and with the vertical body andresting upon the stepped top edges of said partitions to form asubstantially conical structure, means securing said grate platestogether in vertically spaced overlapping relation, means for rotatingthe base plate and elements supported thereby about the vertical body,said vertical body being formed to facilitate the discharge of air intothe areas between the said partitions, and an upstanding lip formed atthe outer edge of each grate plate and projecting upwardly to a planelying above the bottom of the next overlying grate plate.

7. In a grate of the character described, a vertically disposed centralbody of circular cross section and having a surrounding flange at itslower end, a circular base plate having a central opening through whichthe vertical body projects, having a bearing surface on its under sideand surrounding the aperture and resting upon said flange, a segmentalannulus secured to the top of said plate about its outer edge, aplurality of vertically disposed partitions carried by the plate andextending radially thereof from the central body and having wipingcontact with the latter, each of said partitions being of graduallydecreasing height from its inner to its outer end, a, grate unitcomprising a plurality of sections each consisting of a series ofarcuate grate plates of different diameters arranged in overlappingvertically spaced relation about a common axis and means securing thegrate plates together in spaced relation whereby the unit assumes asubstantially conical form, said sections being supported upon saidpartitions and joined to .form a coaxially arranged series of annularmembers, means forming a part of each section having abutting relationwith the said segmental annulus for retaining the sections in positionand means for rotating the partition supporting plate, said central bodybeing adapted to facilitate the discharge of air into the areas betweenthe partitions.

CHRISTIAN M. SHOTT.

